INSECTS IN HERCULES
ARTHROPODS
Arthro = Joint
Poda = Foot Appendage
CHARACTERISTICS
• Have exoskeleton which is molted several times during their lives. Beneath, a new soft skeleton forms, eventually hardening after the old exoskeleton is shed.
• Jointed legs, three pairs in insects.
• Body divided into two or three parts: head, thorax and abdomen.
• One pair of antennae, no antennae in Arachnids, two pair in Crustacea.
• Many groups undergo metamorphosis.
INSECT DEVELOPMENT
Complete Metamorphosis
1. Egg
2. Larva
(caterpillar in moths and butterflies)
3. Pupa (transition stage)
4.
Adult butterflies, moths, flies, beetles, ants, wasps and
bees.
Incomplete Metamorphosis
1. Immature nymph hatches from egg.
2. Grows, develops wings and by stages becomes an adult.
Dragonflies, damselflies, grasshoppers, true bugs, cicadas.
Simple Pattern
1. Newly hatched insect resembles adult.
2. Grows, molts till reaches adult size.
Silverfish,
springtails, spiders (Arachnids) also follow simple pattern development.
Insects (Class Insecta)
and
Spiders (Class Arachnida)
CLASS INSECTA
ORDER ODONATA
Dragonflies and Damselflies
Also
called Darning Needles
About
400 species occur in
Both
have large compound eyes. In dragon flies the eyes nearly cover the head. In
damselflies the eyes bulge to the side.
Their
four powerful wings move independently, enabling them to fly forward and
backward. Their long legs are used to hold insects captured in flight.
Both
mate in flight. The eggs are deposited in water or onto plants in or near
water. The nymphs are predators that capture insects, tadpoles, even small
fish. When fully grown the nymph crawls out of water, splits the outer skin
lengthwise on the upper surface and the adult emerges.
ORDER ORTHOPTERA
Grasshoppers
Order
name means “straight wing” referring to the forewings. Hind wings are broad and
membranous and are folded flat, hidden under the forewings.
Metamorphosis
is incomplete, with nymphs resembling the adults except they gradually attain
wings.
Males
are known for the musical sounds made when they rub together roughened portions
of their wings or legs. This “music” serves as a form of warning, a way to
establish territory, or a move in courtship.
The
order includes 1,000 species in
A
humpbacked cricket up to 2" in length and wingless. Their threadlike
antennae are as long as their bodies or longer. The head is large with a wide
space between small compound eyes and jaws.
They
feed on other insects, plant roots, decaying vegetation and potato tubers.
Active both day and night, these crickets often leave distinctive smooth tracks
on dusty roads by dragging their bulky abdomens.
Adults
are very slow-moving, particularly during mating season. The female often
devours her mate. Females prepare a depression in the soil for masses of oval
white eggs. They usually produce one
generation a year.
ORDER
HOMOPTERA
Spittlebugs (Froghoppers)
Called
froghoppers because adults are shaped rather like tiny frogs.
Female
spittlebugs make a froth on plant stems and grasses to cover their eggs. The
young nymphs make a froth also to cover themselves while feeding on plant
juices. Adult froghoppers hop from plant to plant and seldom fly.
ORDER COLEOPTERA
Ladybug Beetles
During
the Middle Ages, these beetles rid grapevines of insect pests and, in
appreciation, were dedicated to “Our Lady”, hence the common name. We have over
350 species in this country, though the family is world-wide.
Most
ladybugs have round, shiny red, orange or yellow bodies spotted with black.
Both adults and larvae are predators, mostly of aphids.
The
female may lay up to 500 eggs during a lifespan of a few months. Larvae feed, then
pupate. They produce many generations a year if food supply is good.
Huge
swarms of ladybugs fly into canyons. They overwinter on leaves and plants and
return to valleys in spring.
Acorn Weevil (Curculio
spp.)
A
small beetle with mouthparts modified into a downward-curving beak or snout.
Females bore into acorns, seeds and stems to lay eggs. They often seal the
openings with fecal pellets that look like white dots on the outside of dry acorns.
Larvae
feed and pupate inside. One acorn weevil larva can completely consume a small
scrub oak acorn.
While
it lives, the acorn protects the weevil larvae from most predators, shelters
them from weather, and keeps them moist, cool, and away from sunlight. It also
provides a diet rich in fats and carbohydrates.
Adult
weevils are active from June through August producing one generation a year,
corresponding to the acorn crop.
Beetles occupy the
largest order in the animal kingdom, containing a third of all known insects-
300,000 species worldwide and about 30,000 species in
ORDER
LEPIDOPTERA
Butterflies have 4 wings
covered with scales. They are usually very colorful. They attract mates by
color. They fly only during the day. Butterflies have an enlarged club at the
end of each antenna. At rest, butterflies usually hold wings together
vertically over the body.
Moths have 4 wings
covered with scales. Most have somber colors and fly at night. Moths emit
chemicals to attract mates. Moths have threadlike or feathery antennae, no
clubs on the ends. At rest, moths fold wings over the body, curled around the
body, or flat against a support.
Butterflies
Monarch (Danaus
plexippus)
Our
best known butterfly with orange and black wings. A long
distance
migrator; west in winter to coastal
disagreeable
flavor, caused by their diet, makes birds avoid them.
Lorquin’s Admiral (Limenitis
lorquini)
Orange
tip on forewings and a white band on both wings. Frequents stream courses and
moist meadows. Flies from May until fall. Feeds on willow, cottonwood, poplar
and sometimes orchard trees.
Pale Swallowtail (Papilio
eurymedon)
A
butterfly of hills and canyons. Overall pale yellow with black stripes and
black tail-like projections from the hind wings. Swallowtails are attracted to
water as well as flowers. Caterpillars feed on coffee berry and ceanothus.
California Sister (Limenitis
bredowii callfornica)
Similar
to Lorquin’s Admiral but has blue lines on undersides of wings. Frequents upper
branches of live oaks, on which the larvae feed. The butterfly rarely sips
nectar from flowers but is often attracted to water.
Painted Lady (Cynthia
cardui)
Is
said to be the most widely distributed butterfly in the world. Forewings above
are orange marbled with black, with white bars near the wing tips. Sometimes
found in great migrations flying a few feet above the ground. Such flights may
last for days. Feeds on thistles, nettles, mallows and many other plants.
Buckeye Butterfly (Junonia
coenia)
Light
brown color with large multicolored spots on both the hind and forewing. Caterpillar
feeds on snapdragon, monkey flowers, plantain and other herbs.
Edith’s Checkerspot (Euphydryas
editha bayensis) Colors vary from
black heavily “checkered” with yellow or orange. Food plants are usually
members of the Figwort family; Bee Plant, Monkey Flower, Indian Paint Brush,
and others. Listed as threatened on the US Endangered Species list.
Tent Caterpillar Moths (Malacosoma constrictum)
Moths
are heavy-bodied, hairy and dull-brown. Adults do not feed and have a very
small proboscis or none at all. Males’ antennae have two feathery branches on
each segment. Caterpillars live together in silken tents, often on oak trees
and ceanothus shrubs on which they feed.
ORDER DIPTERA
Flies
Flies
are easily distinguished from other insects because they have only one pair of
normal wings. Most flies have large compound eyes and mouthparts that are
modified for piercing, lapping, or sucking fluids.
Flies
exhibit complete metamorphosis. The larvae are called maggots and live in soil,
decaying material or as parasites of vertebrates, snails and other insects.
Valley Black Gnat (Leptoconops
carteri)
The
most bothersome species, a tiny black fly that torments both animals and humans
as it buzzes in our noses and eyes in the summer looking for sweat secretions.
They also occasionally bite us.
Mosquitoes
Mosquitoes
are slender, delicate flies with mouthparts modified into a long tubular
proboscis adapted for piercing and sucking. Nearly all of the females suck
blood but the males feed only upon plant juices, if at all.
Most
females need a lot of protein in order to lay eggs. They obtain this protein
from the blood of reptiles, birds, or mammals, transmitting malaria,
encephalitis and other diseases in the process. Eggs are laid on the water’s
surface, either in clumps or singly. Habitat choices for laying eggs range from
tree holes, rain-filled footprints, cans, old tires or in permanent fresh and
even brackish water.
The
larvae are called wrigglers and most species have a tail respiratory tube which
is projected through the surface film to obtain oxygen. Wrigglers feed on algae
and bits of organic debris. A few species are predaceous and feed on other
mosquito larvae.
The
larvae pupate and the adults soon emerge from the floating pupae. Adults mate
soon after emergence, and soon after that, the males die. More than several
generations a year may be produced.
ORDER HYMENOPTERA
Honey Bee (Apis mellifera)
These
bees are not native to
Pollen
is collected on bee’s body hairs and then brushed into “pollen baskets” on its
legs. Like nectar, the high protein pollen can be eaten immediately or stored
in wax cells. Humans benefit greatly from bees’ pollination of many flowering
plants.
Ants
Ants
live in colonies with a complex social structure, in underground tunnels or in
dead wood. An ant family has its own
distinct odor. As an ant crawls along he leaves behind (formic acid) his family
odor. Each ant finds his way back to the family by following this secretion. In
some colonies winged males and females emerge from the nest and mate. After mating, the males die and the females
lose their wings and return to the ground to start a new colony. When
disturbed, most ants are capable of biting or stinging people.
Ant species
• Little Black Ant (Monomorium minimum) 0.1"
• Introduced Argentine Ant 0.1"
• Carpenter Ant (Camponotus spp.)
Largest of our species, 0.5"
Yellow Jackets (Vespula
spp.)
Yellow
Jackets are short, stocky wasps, boldly marked with black and yellow banded abdomens.
These wasps make nests of “paper” that they make by chewing bits of wood or
leaves. Most yellow jackets nest in the ground.
Like
other social insects, these wasps have a “caste” system made up of queens,
males, and sterile female workers.
The
larvae are reared in the cells of the nest and are fed pre-chewed insects and
other “meat” by adults. Adults eat only nectar.
When
cold weather begins, all die except mated females, which over-winter among
litter and in the soil. They begin new colonies by them-selves the following
spring.
Females
can sting repeatedly at the least provocation.
Gall Producing Insects
Cynipid
wasps are by far the most common groups of gall insects in
The
chemical stimulus leading to gall formation may originate when a female gall
insect stings a leaf, stem, or branch and injects a fluid rich in nucleic acids
and protein along with its eggs.
The
reaction of the plant to the invading organism is one of defense. Gall plant
tissue normally swells outwardly from the area of the egg insertion. This
growth usually leaves a chamber or cavity, which becomes the feeding territory
of the larvae. Adult wasps chew their way out of the galls and drop to the
ground. Many gall inducers emerge in spring, timed with the development of new
shoots and leaves.
The
life cycles of most cynipid wasps and gall sawflies are complicated and have
yet to be completely worked out.
Some Gall Inducers
Live Oak Gallfly (Callirhytis
pomiformis)
Willow Apple Gall Sawfly (Pontania
Coyote Brush Gall Midge (Rhopalomyia
californica) (Order Diptera)
ORDER HEMIPTERA
(True Bugs)
CHARACTERISTICS
• The fore wings fold flat over the back. They are usually leathery at the base and membranous at the tip and overlap each other.
• The hind wings, which are the flying wings, are uniformly membranous and slightly shorter than the fore wings
• True Bugs have sucking mouthparts in the form of a beak.
Water Boatmen (Corixa
Spp.)
Slender
true bugs with long hind legs flattened for swimming. Air taken at the surface
usually surrounds the insect in a silvery envelope. Water Boatmen must hold on
to some object in order to remain submerged. Adults are strong fliers and
commonly attracted to lights. They feed on algae and decaying plant and animal
matter sucked from the pond bottom. Oval eggs are cemented to underwater
supports. They hatch in 7-15 days. Nymphs resemble adults except that they may
change
color
several times and are wingless. In
Water
Boatmen species in all of its life stages.
Water Strider (Gerris
remigis)
Slender,
dark, long-legged true bug that skates or jumps about on
the
surface film of water. Mostly wingless. They feed on aquatic insects including
mosquito larvae that rise to the surface, and terrestrial insects that drop
into water.
Cylindrical
eggs are laid in parallel rows on an object at water’s edge. Nymphs mature in
about 5 weeks. Adults live many months and sometimes over winter under fallen
leaves on land near water.
Sometimes
called “Jesus Bugs” because they “walk” on the water.
CLASS
ARACHNIDA
ORDER ARANEAE
CHARACTERISTICS
• Have two body parts, head fused with chest, and abdomen.
• Four pairs of jointed legs.
• No antennae
• Usually 8 simple eyes in different arrangements.
• Book lungs.
• Pedipalps located between the jaws and first legs. Used by male
spiders to transfer sperm to female during mating.
Turret
Spider (Atypoides riversi)
Turret
Spider is in the family of Folding Trapdoor Spiders. Builds silk-lined burrow
in soil and elongates the lining up into a turret-like opening, often
camouflaged with leaves and lichen. Nocturnal, when foraging for food it folds
the ends of the turret together, closing it temporarily.
Orb
Weavers
Most orb weavers spin
spiraling orb webs on support lines that radiate outward from the center. Many
orb weavers replace the entire web each night with a new one, spun in complete
darkness by touch alone.
Black & Yellow Argiope (A. aurantia)
Web usually has crossed zigzag bands which makes for a
stronger web, protective against spider color. Spider hides behind it, birds
can see it well so don’t fly through it.
Female fills egg sac, attaches
it to one side of web close to her resting position, and then dies. Eggs hatch
in autumn, over winter in sac, disperse in spring. Seems to prefer sunny sites
with little or no wind.
Crab
Spider (Misumena vatia)
These small, crablike spiders
live in bark or trees or under rocks on the ground. Most are well camouflaged.
Female guards her eggs in a silken cocoon attached to plants but she usually
dies before spiderlings emerge.
Funnel
Web Weavers (Agelenopsis spp.)
These spiders spin sheet webs
of nonsticky silk. There is a funnel extending off from the center to one edge,
where the spider hides. There is a 3" barrier web over the top. When a
flying insect hits this barrier, it falls into sheet below. The spider rushes
out of funnel, bites its insect prey, drags it back to the funnel and feeds.
Jumping
Spiders
These spiders have sharpest
vision of all spiders, and are excellent hunters. As they leap on a victim, silk comes out from
the spinnerets, creating a long silken dragline. They do not spin webs, but
make little silken shelters under bark, stones, or leaves.
Wolf
Spiders
They
run on the ground or over stones and sometimes up plants. They do not spin
webs. Spiderlings are carried on the females back until ready to disperse.
Ticks feed on the blood of
mammals. The female, engorged with blood, lays a large number of eggs on the
ground and dies.
The eggs hatch in a few days
in warm weather. Hatchlings climb up plants and latch on to a passing host.
They drop off after a meal, molt, and climb to another host, repeating the
process until full grown.
OTHER ARTHROPODS
CLASS CRUSTACEA
ORDER ISOPODA
Sowbugs
Sowbugs are neither bugs nor
insects. They are harmless land crustaceans, related to aquatic animals such as
shrimp, crabs, and crayfish. Sowbugs breathe with gills and cannot live long
without high humidity.
These small, flattened, jointed animals live in and
under rotting logs, under stones or in the soil. At night, these animals leave
their crevices to forage for food consisting of plants and tiny animals. As a
defense, some of these animals are able to roll up into a ball and are known as
“pillbugs”.
CLASS DIPLOPODA
Millipedes
(Narceus americanus)
Millipedes are slow moving
wormlike animals found in damp, dark places, beneath rocks, wood, and leaves or
in soil. Usually blackish in color and many-legged with 2 pairs of short legs
on most body segments. Feed on plants or decaying material. Etc.
Many species are able to emit
a foul-smelling fluid through openings along sides of the body. The substance
discourages predators and is poisonous to some creatures.
CLASS CHILOPODA
Centipedes
(Scuitgera coleoptrata)
Centipedes
are wormlike predaceous animals found in
nearly all land habitats including houses; under litter bark and rocks during
the day. Legs arranged 1 pair per body segment. Feed on insects and other small
arthropods. Centipedes are able to deliver a painful sting from poison-bearing
claws on the first pair of legs.
PHYLUM ANNELIDA
CLASS OLIGOCHAETA
Earthworms
Found worldwide except in the
driest and coldest parts of the world. Their simple design consists of two
tubes- the body and the gut- separated by a fluid-filled cavity. They eat their
way through the soil, depositing piles of “worm castings” on the surface of the
ground near their burrows. Decaying matter is digested and redistributed, and
the soil is mixed and loosened, carrying air and moisture to plant roots and
other soil creatures. It’s estimated earthworms have increased soil
productivity as much as 80%.
Earthworms are even able to
live in fresh water provided there is enough oxygen. Two halves of a broken
worm can regenerate and live providing large enough pieces exist.
PHYLUM MOLLUSCA
CLASS GASTROPODA
Banana
Slug (Ariolimax spp).
Slugs and snails belong to the
group called gastropod, meaning “belly foot”. Slugs are land snails that have
no shell. Slugs make a slimy substance that help them move along. Slugs’ slime
is so protective that the slug can climb over a very sharp knife unharmed.
Banana slugs are butter yellow
color, and have two sets of tentacles on the head. The upper, longer pair are
the eyes and can move independently. The lower, shorter tentacles are for
feeling and smelling.
Inside the mouth is a toothed
tongue called a radula. This radula allows the slug to rasp food into pulp and
pull the food into the esophagus. Banana slugs are champion decomposers and eat
living and decaying vegetation; roots, fruit, seeds, bulbs, lichen, algae,
fungi, poison oak, animal droppings, and carcasses.
Banana slugs are hermaphrodites.
Each animal has both male and female reproductive organs. They mate at all
times of the year. After penetration they exchange sperm, each producing eggs
and sperm simultaneously. They often become stuck and cannot separate, so they
take turns gnawing off the stuck organ or organs. The severed male organ
possibly regenerates.
Slugs deposit a clutch of 30
or more eggs in a hole or crevice where ground water and humidity are high.
Three to eight weeks later the eggs hatch and the tiny slugs are on their own.
Banana slugs must live in a moist environment and can
take up water through the skin so do not need to drink water. They actually
enhance with their deposits of nitrogen-rich fertilizer in the redwood forest.
They help ensure the survival of the trees that, in turn, give them moisture
and protection from the drying sun.
Many animals find slimy
creatures distasteful. However, banana slugs have many predators including
garter snakes, foxes, moles, porcupines, beetles, pacific giant salamander,
ducks, crows, millipedes,
Species
of Banana Slugs
Ariolimax californicus
A.californicus brachyphallus (short penis) A.dolichophallus
(long penis)
GLOSSARY
Abdomen - The hindmost part of an insect’s body.
Antenna - One of a pair of sensory organs on the head of an
insect, also called “feelers”. Primarily organs of smell and taste. (Pl.
antennae)
Exoskeleton - A supporting structure on the outside of the body,
enclosing all living cells.
Larva - Immature,
wingless feeding stage between egg and pupa. (Pl. larvae)
Metamorphosis - The transformation of an immature to a mature insect
following the feeding (nymphal and larval) stages.
Molt - The shedding of the confining outer layer of the
body (exoskeleton) to permit growth or metamorphic change.
Nymph - A young insect that resembles an adult, wings develop
externally as pads, lives on land and does not have a pupa stage.
Pedipalps - Second pair of appendages in arachnids. Usually
leg-like in female spiders but enlarged at the tip in males and used as a
special organ for transferring sperm.
Proboscis - A prolonged set of mouthparts adapted for reaching
into or piercing a food source.
Pupa - The transitional stage of insects during which the
larva changes into the adult form completing its metamorphosis.
Spinneret
- One of the 2-4 pairs of nozzlelike
appendages below the rear part of a spider’s abdomen, through which silk is
extruded and manipulated to form the strands of a web.
Thorax - The
middle portion of an insect’s body, bearing the legs and wings.
REFERENCES
Reference: Plant Galls of the
Ronald A. Russo, 1979, Boxwood Press
Audubon
Society Field Guide to North American Insects and
Spiders, Milne and Milne, Chanticleer Press, Inc.
Insects, Borror and
White, Peterson Field Guides.
Butterflies of the
J.
W. Tilden, U. C. Press, Berkeley, CA. 1965.
Spiders
and Their Kin, Golden Guide, Levi
and Levi.
Butterflies
and Moths, Golden Guide, Mitchell
and Zim.
Insects, Golden Guide, Zim and Cottam.
Dr.
John Hafernik, Professor of Biology, San Francisco
